A motorcycle including a disk brake caliper for applying a braking force to a wheel, a caliper bracket for fixing the disk brake caliper to the body frame side, and a wheel speed sensor attached to the caliper bracket in order to detect the rotating speed of the wheel is known. See, e.g., Japanese Patent Laid-open No. 2007-78549 (“JP '549”).
In FIG. 3 of JP '549, a rear wheel 14 (the same reference symbols as in the document are used herein) is rotatably (swingably) mounted to an end part of a swing arm 12 through an axle 15, and a brake caliper 28 is mounted to the swing arm 12 through a brake caliper holder 27 extending toward the lower side. A rotation sensor 40 for detecting the rotating speed of the rear wheel 14 is mounted to the brake caliper holder 27, and a blocking wall 53 for receiving a foreign matter G such as a small stone flung up from a road surface during running is integrally provided in the periphery of the rotation sensor 40.
The blocking wall 53 described in JP '549 prevents foreign matters G flying from the lower side, the front side or the rear side, from colliding against the rotation sensor 40. However, the addition of the blocking wall 53 leads to an increase in vehicle weight.
Also, since the rotation sensor 40 is exposed to a lateral side of the vehicle, collision of a foreign matter against the rotation sensor 40 cannot be obviated in the case where the foreign matter projects toward the rotation sensor 40 from the exposed lateral side. Thus, an additional member for covering the rotation sensor 40 or the like member may be separately provided in order to reduce the likelihood of foreign matter colliding against the rotation sensor 40. However, this leads to a further increase in the number of component parts and/or increase in overall vehicle weight.